The U.S. Pat. No. 4,688,517 discloses an apparatus for processing tissue samples. On a rotatable plate a plurality of processing containers is provided for the sample processing. The plate is rotatable, so that the processing containers can be transported to a processing station at which the tissue samples are successively immersed into different processing liquids. For a suitable tempering of the actually used processing liquids a heating and cooling device is permanently mounted to the housing of the apparatus. The plate is not only rotatable but also raisable and lowerable in the direction of the axle. The processing containers are only snapped into recesses of the transport plate. A firm and defined placement of the processing containers on the plate is not provided.